rlogind(1M)
NAME
in.rlogind, rlogind - remote login server
SYNOPSIS
/usr/sbin/in.rlogind
DESCRIPTION
in.rlogind is the server for the rlogin(1) program. The
server provides a remote login facility with authentication
based on privileged port numbers.
in.rlogind is invoked by inetd(1M) when a remote login con-
nection is established, and executes the following protocol:
o The server checks the client's source port. If the
port is not in the range 512-1023, the server aborts
the connection.
o The server checks the client's source address. If an
entry for the client exists in both /etc/hosts and
/etc/hosts.equiv, a user logging in from the client is
not prompted for a password. If the address is associ-
ated with a host for which no corresponding entry
exists in /etc/hosts, the user is prompted for a pass-
word, regardless of whether or not an entry for the
client is present in /etc/hosts.equiv. See hosts(4)
and hosts.equiv(4).
Once the source port and address have been checked,
in.rlogind allocates a pseudo-terminal and manipulates file
descriptors so that the slave half of the pseudo-terminal
becomes the stdin, stdout, and stderr for a login process.
The login process is an instance of the login(1) program,
invoked with the -r.
The login process then proceeds with the pam(3PAM) authenti-
cation process. See SECURITY below. If automatic authenti-
cation fails, it reprompts the user to login.
The parent of the login process manipulates the master side
of the pseudo-terminal, operating as an intermediary between
the login process and the client instance of the rlogin pro-
gram. In normal operation, a packet protocol is invoked to
provide <Ctrl-S> and <Ctrl-Q> type facilities and propagate
interrupt signals to the remote programs. The login process
propagates the client terminal's baud rate and terminal
type, as found in the environment variable, TERM; see
environ(4).
USAGE
rlogind and in.rlogind are IPv6-enabled. See ip6(7P).
SECURITY
in.rlogind uses pam(3PAM) for authentication, account
management, and session management. The PAM configuration
policy, listed through /etc/pam.conf, specifies the modules
to be used for in.rlogind. Here is a partial pam.conf file
with entries for the rlogin command using the "rhosts" and
UNIX authentication modules, and the UNIX account, session
management, and password management modules.
rlogin auth sufficient pam_rhosts_auth.so.1
rlogin auth requisite pam_authtok_get.so.1
rlogin auth required pam_dhkeys.so.1
rlogin auth required pam_unix_auth.so.1
rlogin account required pam_unix_roles.so.1
rlogin account required pam_unix_projects.so.1
rlogin account required pam_unix_account.so.1
rlogin session required pam_unix_session.so.1
With this configuration, the server checks the client's
source address. If an entry for the client exists in both
/etc/hosts and /etc/hosts.equiv, a user logging in from the
client is not prompted for a password. If the address is
associated with a host for which no corresponding entry
exists in /etc/hosts, the user is prompted for a password,
regardless of whether or not an entry for the client is
present in /etc/hosts.equiv. See hosts(4) and
hosts.equiv(4).
If there are no entries for the rlogin service, then the
entries for the "other" service will be used. If multiple
authentication modules are listed, then the user may be
prompted for multiple passwords. Removing the
"pam_rhosts_auth.so.1" entry will disable the
/etc/hosts.equiv and ~/.rhosts authentication protocol and
the user would always be forced to type the password. The
sufficient flag indicates that authentication through the
pam_rhosts_auth.so.1 module is "sufficient" to authenticate
the user. Only if this authentication fails is the next
authentication module used.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWrcmds |
|_____________________________|_____________________________|
SEE ALSO
login(1), rlogin(1), in.rshd(1M), inetd(1M), pam(3PAM),
environ(4), hosts(4), hosts.equiv(4), inetd.conf(4),
pam.conf(4), attributes(5), pam_authtok_check(5),
pam_authtok_get(5), pam_authtok_store(5), pam_dhkeys(5),
pam_passwd_auth(5), pam_unix(5), pam_unix_account(5),
pam_unix_auth(5), pam_unix_session(5)
DIAGNOSTICS
All diagnostic messages are returned on the connection asso-
ciated with the stderr, after which any network connections
are closed. An error is indicated by a leading byte with a
value of 1.
Hostname for your address unknown.
No entry in the host name database existed for the
client's machine.
Try again.
A fork by the server failed.
/usr/bin/sh: ...
The user's login shell could not be started.
NOTES
The authentication procedure used here assumes the integrity
of each client machine and the connecting medium. This is
insecure, but it is useful in an ``open'' environment.
A facility to allow all data exchanges to be encrypted
should be present.
The pam_unix(5) module might not be supported in a future
release. Similar functionality is provided by
pam_authtok_check(5), pam_authtok_get(5),
pam_authtok_store(5), pam_dhkeys(5), pam_passwd_auth(5),
pam_unix_account(5), pam_unix_auth(5), and
pam_unix_session(5).
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